The invention relates to space station clamping and pointing devices. In particular, a device for attaching to a space station handrail and providing precision positioning of a attached payload under orbital conditions is provided.
In order to elevate the chances of success for the International Space Station Alpha program, the National Aeronautics and Space Administration began an effort to study environmental risks at space station handrail altitudes. Four experiments were proposed, each of which would have to be mounted to the existing Russian MIR space station handrail without modification to the Russian manufactured docking module. In two of the cases, ram/wake viewing of the experiment was required which required MIR flight orientation data. However, analysis of this data would not be complete before the deployment of the experiments.
In light of these requirements, NASA undertook the development of a clamp for attaching and positioning a common carrier in which each of the experiments could be mounted. The attachment end of the clamp was required to exert a force of 1000 newtons on a space station handrail; however, the exact dimensions of the space station handrail were unknown--thus, it was necessary that the clamp be able to provide a consistent 1000 newton force over the entire range of possible space station handrail thicknesses. Additionally, the space station handrail clamp should be able to exert pressure at several points, both to increase the stability of the clamp and to prevent a concentrated, and perhaps deforming, load from being applied at one point on the space station handrail. Finally, since the clamp would be deployed during free-floating extravehicular activities (EVAs), it was important that the clamp mechanisms be large enough to facilitate operation by an astronaut wearing a complete spacesuit, that the mechanism itself have no sharp corners or edges, and that the device require no more than a 120 newton force exerted through one hand during installation.
The pointer end of the device also had strict requirements to achieve the precision positioning required for the experiments. First, the pointer had to provide sufficient strength to hold the position of the attached device in accelerations of up to 0.5 g (4.9 m/s.sup.2). However, to prevent accidental deformation of the space station handrail to which the device was attached, the payload had to be able to slip in position when a kick load of 125 pounds or greater was applied. Finally, the pointer also had to meet the same requirements as the space station handrail attachment in terms of installation by an astronaut during EVA.
Finally, all components of the device had to be suitable for spaceflight; specifically, they had to retain operability at extreme low temperatures, be constructed of materials which would not outgas, operate without lubrication, and use dissimilar materials at points of contact to prevent cold welds from occurring.
No prior art attachment and positioning devices met the stringent requirements necessary for the MIR space station handrail deployment.